Now, thanks to Arizona State University researcher Zackary Graham and his colleagues, we can add the "unicorn of the seas," the narwhal, to the list. They found that male tusks can have over 4 ...

Since he was a child, Martin Nweeia, DMD (DEN ’84), has been fascinated with teeth—from the human variety to the 9-foot spear-shaped tusk that grows out of the head of the narwhal, an Arctic whale.

The male’s iconic, spiralling tusk is in fact a canine tooth. It can grow up to three metres long. Narwhal tusks were once a highly sought-after commodity. They were often collected by Inuit and ...

The most extraordinary feature of the narwhal is the long, spiral tusk which always has a left- handed spiral. No one is sure why it twists this way. The tusk, which measures up to 3m in length ...